Blends of aromatic polycarbonate resin, olefin polymers or copolymers and acrylate- or methacrylate-copolymer resins

Abstract

Thermoplastic molding compositions are described which comprise an admixture of (a) an aromatic polycarbonate resin, (b) an olefinic polymer or copolymer and (c) a third component which is a copolymer of an olefin and an acrylate, methacrylate, acrylic acid or methacrylic acid. The presence of the third component enhances impact strength in thicker sections and improves weld line strength.

What is claimed is: 
     
       1. A thermoplastic composition, comprising an intimate blend of (a) from about 55 to about 93 parts by weight of an aromatic polycarbonate resin;   (b) from about 3.5 to about 30 parts b weight of a polyolefin homopolymer an olefin copolymer or terpolymer made solely from olefin monomers or mixtures thereof; and   (c) from about 3.5 to about 15 parts by weight of a third polymeric component comprising a copolymer of one or more olefins and a monomeric acrylate, methacrylate, acrylic acid or methacrylic acid, the amount of (c) being at least sufficient to impart to the blend a resistance to impact failure in thick sections greater than that possessed by (a), and a weld line impact strength better than that possessed by (a) and (b) in combination the total weight of (a), (b), and (c) combined is 100 parts.   
     
     
       2. A composition according to claim 1, in which the aromatic polycarbonate resin has the formula ##STR3## wherein A is a divalent aromatic radical of a dihydric phenol. 
     
     
       3. A composition according to claim 1, in which the aromatic polycarbonate resin has the formula ##STR4## wherein R 1  and R 2  are, independently, hydrogen, alkyl having from 1 to about 10 carbon atoms, or phenyl; X is, independently, alkyl having from 1 to about 10 carbon atoms, chloro, bromo or hydrogen; p and r are independently, from zero to 4; and n represents the total number of monomer units and is an integer of at least about 30. 
     
     
       4. A composition according to claim 1, in which the aromatic polycarbonate resin is poly(bisphenol A carbonate). 
     
     
       5. A composition according to claim 1, in which the olefin resin (b) is selected from the group consisting of polyethylene, polypropylene, polyisobutylene, a copolymer of ethylene and propylene, terpolymers of ethylene, propylene and a diene copolymer of ethylene and butene-1 and mixtures thereof. 
     
     
       6. A composition according to claim 1, in which component (b) comprises polypropylene. 
     
     
       7. A composition according to claim 6, in which component (b) comprises a terpolymer of ethylene, propylene and a diene. 
     
     
       8. A composition according to claim 1, in which component (b) comprises a copolymer of ethylene and propylene. 
     
     
       9. A composition according to claim 1, in which component (b) comprises a linear low density polyethylene. 
     
     
       10. A composition according to claim 1, in which component (c) comprises a copolymer of ethylene and ethyl acrylate. 
     
     
       11. A composition according to claim 1, in which component (c) comprises a terpolymer of ethylene, propylene and acrylic acid. 
     
     
       12. A composition according to claim 1, wherein a reinforcing amount of a filler is present. 
     
     
       13. A composition according to claim 12, wherein said filler comprises glass fiber. 
     
     
       14. A composition according to claim 1, wherein a flame retardant effective amount of a metal salt of an organic sulfonic acid is also present. 
     
     
       15. An article which has been molded from a composition according to claim 1, said article being characterized by improved resistance to environmental stress cracking and crazing in comparison with a corresponding article consisting of the aromatic polycarbonate resin alone. 
     
     
       16. A thermoplastic composition comprising an intimate blend of (a) from about 55 to about 93 parts by weight of an aromatic polycarbonate resin;   (b) from about 3.5 to about 30 parts by weight of a polymer made solely from olefin monomers selected from the group consisting of polyolefin homopolymer, an olefin copolymer or terpolymer made solely from olefin monomers and mixtures thereof; and   (c) from about 3.5 to 15 parts by weight of a third polymeric component comprising a copolymer of one or more aliphatic monoalphaolefins and a monomeric acrylate, methacrylate, acrylic acid or methacrylic acid, the amount of (c) being at least sufficient to impart to the blend a resistance to impact failure in thick sections greater than that possessed by (a), and a weld line impact strength better than that possessed by (a) and (b) in combination, the total weight of (a), (b), and (c) combined is 100 parts.